How to blend/mask materials?
Sure, that's the whole point of shading, you create noise patterns and then use them to guide blend or strength input parameters. Here a example:

Separating Uv coordinates makes a gradient in the chosen direction, add centeri it in the plane and then mix it with a noise on linear light mode. Then use that to guide any blend or parameter. 1 of the millions of ways you can mix values to generate masks, the core technique of shading.